Cytokines are small soluble regulatory molecules of the mammalian immune system. They control the growth, function and differentiation of a wide variety of cells and are therefore at the heart of all processes in which the body defends itself from infection of any nature. Banyer et al., 2000, Rev Immunogenet 2, 359-373. Recently six new ligands with limited homology to IL-10 have been identified. (Reviewed in Kontenko, et al., (2002)). Only a very limited amount is known about the function of these IL-10 homologous ligands. Jiang et al., 1995, reported cloning melanoma differentiation associated gene 7 (mda-7), an IL-10 homolog as a protein whose expression is elevated in terminally-differentiated human melanoma cells. Soo et al., 1999, reported expression of the rat mda-7 paralog was linked to wound healing; Zhang et al., 2000, designated the protein c49a and linked it to ras transformation. The protein has also been designated mob-5. The expression of rat mda-7 (c49a) was localized primarily to fibroblast-like cells at the wound edge and base. Soo, et al, 1999, further reported that during wound healing the level of c49a mRNA was transiently elevated 9 to 12-fold above unwounded controls. In addition, expression of rat mda-7 (mob-5) was demonstrated to be induced by expression of oncogenic ras. Moreover, mob-5 and its putative receptor are oncogenic ras specific targets; mob-5 binds to the cell surface of ras-transformed cells but not of parental untransformed cells. Zhang et al., 2000.
Saeki, et al., Oncogene 21(29):4558-66 (2002), reported that in addition to the overexpression of the melanoma differentiation associated gene-7 (mda-7) in vitro resulting in suppression of lung cancer cell proliferation, overexpression of the mda-7 gene in human non-small cell lung carcinoma cells in vivo has an effect on tumor growth. In particular, Saeki, et al., reported that adenovirus-mediated overexpression of MDA-7 in p53-wild-type A549 and p53-null H1299 subcutaneous tumors resulted in significant tumor growth inhibition through induction of apoptosis, and that decreased CD31/PECAM expression and upregulation of APO2/TRAIL were observed in tumors expressing MDA-7. According to the authors, the data demonstrates that Ad-mda7 functions as a multi-modality anti-cancer agent, possessing both pro-apoptotic and anti-angiogenic properties and thus may potentially serve as a therapeutic agent against human lung cancer.
Knappe et al., J Virol 74(8):3881-7 (2000) reported cloning another IL-10 homolog, designated ak155, as a protein expressed by herpes virus saimiri-transformed T lymphocytes.
Gallagher et al., Genes Immunl (7):442-50 (2000) reported the identification and cloning of a gene and corresponding cDNAs encoding a homologue of IL-10, which they designated IL-19. According to Gallagher et al., IL-19 expression was induced in monocytes by Salmonella lipopolysaccharide (LPS) treatment, but IL-19 did not bind or signal through the canonical IL-10 receptor complex, suggesting existence of an IL-19 specific receptor complex, the identity of which remained to be discovered.
Blumberg et al., Cell 104(1):9-19 (2001), also reported cloning a protein with homology to IL-10, which they designated Zcyto10 (GenBank accession number AF224266) or IL-20. Several lines of evidence demonstrate that IL-20 may play a functional role in epidermal development and psoriasis.
Dumoutier, et al., J Immunol 164(4): 1814-9 (2000) reported cloning IL-TIF (IL-10 related T cell-derived inducible factor), an IL-10 homolog, expressed by IL-9 treated murine T cells. Dumoutier, et al., Proc Natl Acad Sci USA 97(18): 10144-9 (2000) and Xie, et al., J Biol Chem 275(40):31335-9 (2000) reported cloning IL-TIF's human orthologue (human IL-22). According to these reports, murine IL-22 expression can be induced by IL-9 in thymic lymphomas, T cells and mast cells in vitro and by LPS in various organs in vivo, and IL-TIF injection induced production of acute phase reactants in mouse liver, suggesting involvement of IL-TIF in the inflammatory response.
With the sequence of the human genome being completed, cytokines and receptors have been discovered “in silico.” Currently there are 11 members of the class II cytokine receptor family with assigned functions. Kotenko, S. V. (2002) Cytokine Growth Factor Rev. 13, 223-240; Kotenko, et al., (2000) Oncogene 19, 2557-2565; Dumoutier, et al., (2002) Eur Cytokine Netw. 13, 5-15; Fickenscher, et al., (2002) Trends Immunol 23, 89-96. These receptors are primarily utilized for signaling by members of two cytokine families, IFN and IL-10. The IFN family is further divided to type I and type II IFNs. The type II group is represented by a single member, IFN-γ, whereas the type I group is comprised of 13 IFN-α species (data were obtained from the website of the National Center for Biotechnology Information with the use of various software tools for analyzing genome and EST databases available at the site.), a single species of IFN-β, IFN-ω and IFN-κ (Lafleur, et al., (2001) J Biol Chem 276, 39765-39771), and a mouse cytokine designated limitin (Oritani, et al., (2000) Nat. Med 6, 659-666) for which a human homolog has not yet been identified (and may not exist).
All known type I IFN genes are clustered on human chromosome 9. There is at least one additional member of this family positioned in the same cluster.
The family of IL-10-related cytokines consists of six members of cellular origin, IL-10, IL-19, IL-20, IL-22, IL-24 and IL-26, as well as several viral cytokines (for review see Kotenko, S. V. (2002) Cytokine Growth Factor Rev. 13, 223-240; Dumoutier, et al., (2002) Eur Cytokine Netw. 13, 5-15; Fickenscher, et al., (2002) Trends Immunol 23, 89-96).
All of these cytokines possess important biological activities. Several members of the IL-10 family are involved in a complex regulation of inflammatory responses. Whereas anti-inflammatory activity of IL-10 (on macrophages) is well characterized (Moore, et al., (2001) Annu. Rev Immunol 19, 683-765), the functions of the other IL-10-related cytokines are not well defined. IL-22 upregulates expression of several acutephase proteins in liver and hepatoma cells, and induces expression of pancreatitis-associated protein (PAPI) in pancreatic acinar cells (Dumoutier, et al., (2000) Proc Natl Acad Sci USA 97, 10144-10149; Aggarwal, et al., (2001) J Interferon Cytokine Res 21, 1047-1053).
IL-20 seems to be involved in regulation of normal skin development because IL-20-transgenic mice display skin abnormalities characterized by altered epidermal differentiation with hypoproliferation of keratinocytes (Blumberg, et al., (2001) Cell 104, 9-19).
The activities of IL-19 and IL-24 are not well characterized. However the fact that they share receptors with IL-20 and IL-22 indicates that they may share at least a subset of biological activities as well. No information about the factional activities or the receptor for IL-26 is currently available.
Type I and type II IFNs are important immunomodulators. Type II or immune IFN (IFN-γ) is a Th1-type cytokine which regulates both innate and adaptive immunity. IFN-γ stimulates cell-mediated immune responses which are critical for mediating protection against infection by intracellular parasites infections (many viruses) and is a part of antiviral defense.
Type I IFNs are well known for their ability to induce antiviral protection in wide variety of cells. They also activate host adaptive and innate immune forces to eliminate viral infections.
Antiviral protection is a highly complex process which involves several levels of defense starting with efforts of an infected cell to prevent the replication of a virus and warn other cells about viral presence, and finishing with the engagement of an entire army of immune protective forces to combat virus propagation in a body. It seems that the main task of a first set of cells undergoing primary infection is to release signals to neighboring cells and immune system in general to alert them about viral presence and to force them to build antiviral protection before a virus infects them. Thus, the next wave of infected cells are better prepared to fight and upon sensing the presence of a virus through various means activate intracellular mechanisms of antiviral protection or even commit suicide (apoptosis) to prevent viral replication (reviewed in Levy, et al., (2001) Cytokine Growth Factor Rev 12, 143-156 and Samuel, C. E. (2001) Clin Microbiol Rev 14, 778-809). These alert signals are also produced by a subset of dendritic cells, which are able to sense the presence of a virus through mechanisms not necessarily involving viral entry into the cells. It is always a race between viral replication and development of cellular and immune defense forces that determines severity, duration and outcome of a viral infection.
Type I IFNs have been known for their ability to induce antiviral protection on both cellular and immune levels. Virus-induced robust production and secretion of IFNs leads to the induction of expression of many proteins with antiviral actions. The most well studied proteins in this respect are double-stranded RNA-activated protein kinase (PKR), 2′,5′-oligoadenylate synthetase (OAS) and Mx proteins. These IFN-inducible proteins prevent viral replication through various mechanisms. dsRNA-activated PKR phosphorylates translation-initiation factor eIF-2α blocking protein synthesis. OAS activates Rnase L which cleaves mRNA and rRNA, thus inhibiting viral replication on both transcriptional and translational levels. Clearly, such drastic measures affect cellular viability; indeed, both enzymes have been implicated in apoptosis.
Mx proteins are GTPases and some of them possess antiviral activity. The mechanism of their action is not completely understood. Mx proteins are found associated with viral ribonucleoprotein complexes and can interfere with their transcriptional functioning and/or trafficking.
Several other IFN-inducible proteins are likely to participate in cellular antiviral protection through mechanisms which remain to be determined. IFNs also modulate function of several type of immune cells (NK, CD-8+ and DC cells) in the direction favorable for clearing viral infection (reviewed in Biron, C. A. (2001) Immunity 14, 661-664 and Le Bon, A. & Tough, D. F. (2002) Curr. Opin. Immunol 14, 432-436).
There is a certain pattern of a ligand-receptor complex composition within the IFN and IL-10 families (Kotenko, 2002). A specific receptor complex for a particular ligand from these families is composed of two different receptor chains with distinct functions. The receptor chains within a given receptor complex can be divided into two types denoted R1 and R2 based on their functions in signaling. Although both R1 and R2 receptors are associated with Jak tyrosine kinases, only R1 type subunits have along intracellular domain, are phosphorylated on Tyr residues after receptor engagement, therefore drive recruitment of various signaling molecules and, thus, determine the specificity of cytokine signaling. R2 type subunits possess a short intracellular domain and support signaling by brining tyrosine kinase to a receptor complex but do not determine the specificity of signaling. The length of the CRF2-12 intracellular domain indicated that this receptor represents the R1 type subunit.
There are five known receptor chains which can combine to form two-chain receptors for one or more of the six known ligands of the IL-10 family, but these five known receptors do not by themselves allow the full potential repertoire of IL-10 homologue signaling to be realized. That is, there are too many ligands and not enough receptors. Furthermore and most importantly, the wide and well-characterized in vivo and in vitro activities of cytokines and their receptors acting in concert demonstrated a clear need for and clinical potential of novel cytokines, cytokine receptors, cytokine mimics, blockers, agonists and antagonists. The present invention addresses these needs directly.
Type I IFNs are thought to exert their biological activities through binding to the specific cell surface receptor complex composed of two chains IFN-αR1 and IFN-αR2c (reviewed in Domanski, et al., (1996) Cytokine Growth Factor Rev 7, 143-151). IFNαR2c is a signal-competent splice variant encoded by the IFNAR2 gene. Studies with IFN-α/β receptor knockout mice in which either subunit of the IFN-α receptor complex have been disrupted demonstrate an essential role for IFN-α signaling in the induction of antiviral resistance (Steinhoff, et al., (1995) J Virol 69, 2153-2158; Muller, et al., (1994) Science 264, 1918-1921; Hwang, et al., (1995) Proc Natl Acad Sci USA 92, 11284-11288} However, the loss of antiviral protection to different viruses is variable in IFN-α receptor knockout mice. For instance, infection with rotavirus proceeds similarly in mice with disrupted or intact IFN-α receptor system (Angel, et al., (1999) J Interferon Cytokine Res 19, 655-659).
IFNs appear to share a common receptor mechanism, the type I IFN-R composed of IFNAR1 and IFNAR2 subunits. IFNAR2 has membrane bound forms that can be short or long and soluble forms. IFN induced receptor dimerization of the IFNAR1 and IFNAR2c chains initiates a signaling cascade that involves tyrosine phosphorylation of the Tyk2 and Jak1 tyrosine kinases and subsequent phosphorylation of the STAT1 and STAT2 proteins (Stark et al., Ann. Rev. Biochem. 67:227-64 (1998); Science 296:1632-1657 (2002)). Association of the phosphorylated STATs with the p48 DNA binding subunit, forms the ISGF3 multisubunit complex that translocates to the nucleus and binds to interferon-stimulated response elements (ISRE) found upstream of the interferon inducible genes. While the type I IFNs bind the same receptor there appears to be subsequent signaling differences. In contrast to the type I IFNs there is only one member of the type II IFN, namely IFN gamma, which is encoded by a single gene (containing three introns) located on chromosome 12. The protein is produced predominantly by T lymphocytes and NK cells, is 166 amino acids in length and shows no homology to type I interferons.
A range of biological activities are associated with IFNs including antiviral, antimicrobial, tumor anti-proliferative, anti-proliferative, enhancement of NK cell activity, induction of MHC class I expression, and immunoregulatory activities. IFN alpha is marketed by Schering Plough (Intron; IFN alpha 2B) and Hoffman La Roche (Roferon; IFN alpha 2A). Therapeutic uses include the treatment of Hairy Cell leukemia, Chronic myelogenous leukemia, low grade non-Hodgkin lymphoma, cutaneous T cell lymphoma carcinoid tumors, renal cell carcinoma, squamous epithelial tumors of the head and neck, multiple myeloma, and malignant melanoma. With regards to viral disease, Interferon alpha has been found to aid the treatment of chronic active hepatitis, caused by either Hepatitis B or C viruses. IFN beta has been demonstrated to have clinical benefit in the treatment of multiple sclerosis. Clinical trials with Interferon gamma have shown potential in the treatment of cutaneous and also visceral leishmanias.
Both recombinant interferons and interferons isolated from natural sources have been approved in the United States for treatment of auto-immune diseases, condyloma acuminatum, chronic hepatitis C, bladder carcinoma, cervical carcinoma, laryngeal papillomatosis, fungoides mycosis, chronic hepatitis B, Kaposi's sarcoma in patients infected with human immunodeficiency virus, malignant melanoma, hairy cell leukemia and multiple sclerosis.
Members of the type I interferon family have also been shown to influence neural cell activity and growth (see, for example, Dafny et al., Brain Res. 734:269 (1996); Pliopsys and Massimini, Neuroimmunomodulation 2:31 (1995)). In addition, intraventricular injection of neural growth factors has been shown to influence learning in animal models (see, for example, Fischer et al., Nature 329:65 (1987)).
IFNs have been used clinically for anti-viral therapy, for example, in the treatment of AIDS (HIV infection) (Lane, Semin. Oncol. 18:46-52 (1991)), viral hepatitis including chronic hepatitis B, hepatitis C (Woo, M. H. and Brunakis, T. G., Ann. Parmacother, 31:330-337 (1997); Gibas, A. L., Gastroenterologist, 1:129-142 (1993)), hepatitis D, papilloma viruses (Levine, L. A. et al., Urology 47:553-557 (1996)), herpes (Ho, M., Ann. Rev. Med. 38:51-59 (1987)), viral encephalitis (Wintergerst et al., Infection, 20:207-212 (1992)), respiratory syncytial virus, panencephalitis, and other therapies, for example, mycosis fungoides and in the prophylaxis of rhinitis and respiratory infections (Ho, M., Annu. Rev. Med. 38:51-59 (1987)).
IFNs have been suggested for anti-parasite therapy, for example, IFN-gamma for treating Cryptosporidium paryum infection (Rehg, J. E., J. Infect. Des. 174:229-232 (1996)).
Anti-bacterial: IFNs have been used clinically for anti-bacterial therapy. For example, IFN-gamma has been used in the treatment of multidrug-resistant pulmonary tuberculosis (Condos, R. et al., Lancet 349:1513-1515 (1997)).
Interferon therapy has been used in the treatment of numerous cancers (e.g., hairy cell leukemia (Hoffmann et al., Cancer Treat. Rev. 12 (Suppl. B): 33-37 (1985)), acute myeloid leukemia (Stone, R. M. et al. Am. J. Clin. Oncol. 16:159-163 (1993)), osteosarcoma (Strander, H. et al., Acta Oncol. 34:877-880 (1995)), basal cell carcinoma (Dogan, B. et al., Cancer Lett. 91:215-219 (1995)), glioma (Fetell, M. R. et al., Cancer 65: 78-83 (1990)), renal cell carcinoma (Aso, Y. et al. Prog. Clin. Biol. Res. 303:653-659 (1989)), multiple myeloma (Peest, D. et al., Br. J. Haematol. 94:425-432 (1996)), melanoma (Ikic, D. et al., Int. J. Dermatol. 34:872-874 (1995)), myelogenous leukemia, colorectal cancer, cutaneous T cell lymphoma, myelodysplastic syndrome, glioma, head and neck cancer, breast cancer, gastric cancer, anti-cancer vaccine therapy, and Hodgkin's disease (Rybak, M. E. et al., J. Biol. Response Mod. 9:1-4 (1990)). Synergistic treatment of advanced cancer with a combination of alpha interferon and temozolomide has also been reported (Patent publication WO 9712630 to Dugan, M. H.).
IFNs have been used clinically for immunotherapy or more particularly, for example, to prevent graft vs. host rejection, or to curtail the progression of autoimmune diseases, such as arthritis, multiple sclerosis, or diabetes. IFN-beta is approved of sale in the United States for the treatment (i.e., as an immunosuppressant) of multiple sclerosis. Recently it has been reported that patients with multiple sclerosis have diminished production of type I interferons and interleukin-2 (Wandinger, K. P. et al., J. Neurol. Sci. 149: 87-93 (1997)). In addition, immunotherapy with recombinant IFN-alpha (in combination with recombinant human IL-2) has been used successfully in lymphoma patients following autologous bone marrow or blood stem cell transplantation that may intensify remission following translation (Nagler, A. et al., Blood 89: 3951-3959 (June 1997)).
The administration of IFN-gamma has been used in the treatment of allergies in mammals (See, International Patent Publication WO 8701288 to Parkin, J. M. and Pinching, A. J.). It has also recently been demonstrated that there is a reduced production of IL-12 and IL-12-dependent IFN-gamma release inpatients with allergic asthma (van der Pouw Kraan, T. C. et al., J Immunol. 158:5560-5565 (1997)). Thus, IFN may be useful in the treatment of allergy by inhibiting the humoral response. Interferons may be used as an adjuvant or coadjuvant to enhance or simulate the immune response in cases of prophylactic or therapeutic vaccination (Heath, A. W. and Playfair, J. H. L., Vaccine 10:427-434 (1992)), such as in anti-cancer vaccine therapy.
Interferons have been used to treat corneal haze.